Both archiving and refiling features are already implemented in TaskPaper mode and extensively documented. For more details see README.md.

Archiving

The command C-c C-x a (taskpaper-archive-subtree) archives the subtree starting at the cursor position to the location given by taskpaper-archive-location. The default archive location is a file in the same directory as the current file, with the name derived by appending _archive.taskpaper to the current file name without extension. You can also choose what item to file archived items under. For details see the documentation string of the variable taskpaper-archive-location. The subtree is filed below the target item as a subitem. Depending on taskpaper-reverse-note-order, it will be either the first or last subitem.

When the taskpaper-archive-save-context custom option is non-nil, a @project tag with project hierarchy is added to the archived item.

Refiling

The following special commands can be used to move/copy subtree under cursor to other location:

• C-c C-w: Move the subtree under cursor to different (possibly invisible) location (taskpaper-refile-subtree).

• C-c M-w: Copy the subtree under cursor to different (possibly invisible) location (taskpaper-refile-subtree-copy).

This commands prompt the user for an outline path to an item offering standard minibuffer completion for possible target locations. Special completion packages like Ivy or Icicles provide faster and more convenient way to complete the outline path in minibuffer. This is the interface also used by the C-c C-j goto command.

The subtree is filed below the target item as a subitem. Depending on taskpaper-reverse-note-order, it will be either the first or last subitem.

from taskpaper-mode.